The invention refers to a vehicle seat of the type
with a longitudinal guide consisting of at least one floor rail and one seat rail,
with a device for adjustment of the height or inclination of its seat surface, arranged between one seat carrier of the seat surface and the seat rail, and
with a belt attachment on the transmission hump side, whereby the lower end area thereof is fastened to the seat rail and the upper end area supports a seat lock which can accommodate the coupling piece of a safety belt and is located to the side of the seat surface.
If, in case of an accident, the body of a passenger is accelerated against the safety belt, the resulting forces can advantageously be intercepted, with low risk of injury to the passenger, if the belt, which may be designed as a V-belt, has an optimum position in relation to the body of the passenger, particularly to the pelvis. One should thus attempt to ensure that as far as possible, the belt lock has a constant position in relation to the seat surface. This must also be guaranteed when the position of the seat surface is adjusted and moved longitudinally in relation to the chassis. For purposes of constantly retaining the same position of the belt lock in relation to the seat position independently of the longitudinal displacement of the vehicle seat in relation to the chassis, i.e. the displacement between seat rail and floor rail, it is already known how to anchor the belt lock by means of a belt lock attachment on the seat rail, namely that seat rail which is located on the transmission hump side of the seat. In addition, one also attempts to locate the door side belt point on the seat carrier. This design presupposes longitudinal guides which are sufficiently well mounted and cannot be torn out. However, the relative changes caused by the adjustment of the height or inclination of the seat surface are not compensated for or taken into consideration. Rather, the position of the belt lock relative to the seat surface will change when the position of the latter changes due to adjustment of height or inclination. It is possible to compensate for these relative movements by using a flexible attachment for the belt lock, e.g. in the form of a steel wire. However, a belt lock of this nature does not ensure proper position of the belt lock relative to the seat surface. Consequently, a passenger buckling the seat belt must search for the belt lock; it is not always in the same relative position--particularly not after an adjustment of the seat surface. If the height or inclination of the seat surface is adjusted while the seat belt is buckled, the safety belt moves in the coupling piece and relative to the passenger.
Thus, the previously known vehicle seat is not ideal with respect to the position of the belt lock and the safety belt if the seat is adjusted. In case of an adjustment of the inclination or height of the seat surface, it is not possible to blindly reach the belt lock; rather, this will remain fixed in one position. An additional disadvantage is that the safety belt is displaced as a result of an adjustment movement.
It is currently known to reduce the influence of relative movements between seat carrier and floor group on the belt lock by linking a holding rail with stop notches to the floor group, particularly at the transmission hump of a passenger car. During normal seat adjustment movements, particularly a longitudinal displacement of the seat, the upper part, which carries the belt lock, slides on a sword-like part, whereby the two parts do not engage. In case of an accident-induced tensile force on the belt, the upper piece is angled, whereby it bends the sword and hooks into it. Hereby, the tensile forces are transmitted via the sword, which is installed at a slight inclination, from the belt lock into the floor group of the vehicle on the side of the transmission hump. This device is provided primarily to compensate for the longitudinal displacement of a seat, which is also the reason for the basically horizontal arrangement of the sword. In case of an additional seat adjustment, e.g. an adjustment of the height while in the extreme front and the extreme rear positions of the longitudinal guide, a constant position of the belt lock relative to the seat surface can only be achieved at very high costs.